1. Field of the Invention
The present invention relates to an inkjet print device and more specifically the invention is related to an improved maintenance device for an inkjet print head.
2. Description of the Related Art
Nowadays inkjet print devices are used in a wide array of apparatuses in a wide array of applications such as fax, color photo printing, industrial applications etc. In these printing systems liquids, possibly of various colors, is ejected out of an array of nozzles located on the liquid ejecting surface of an inkjet print head to a receiving material, such as a substrate.
A long known problem in inkjet print devices is that the nozzles through which the liquid is projected to the receiving material are blocked by clogging of liquid inside the nozzles and on the print head. This renders certain nozzles inoperable and results in a defective print of deteriorated print quality.
To improve the clarity and contrast of the printed image, recent research has been focused to improvement of the liquids used. To provide quicker, more water fast printing with darker blacks and more vivid colors, pigment based liquids have been developed. These pigment-based liquids have a higher solid content than the earlier dye-based liquids. Both types of liquid dry quickly, which allows inkjet printing mechanisms to forms high quality images.
The combination of small nozzles and quick drying liquid leaves the print heads susceptible to clogging, not only from dried liquid and minute dust particles or paper fibers, but also from the solids within the new liquid themselves.
It is known to counteract or correct the problem of clogging by protecting and cleaning the print head by various methods such as wiping, spitting, capping or purging. Also other methods exist for cleaning an inkjet print head which may include applying solvents as in EP1018430 (HEWLETT PACKARD).
These features designed to clean and to protect an inkjet print head are commonly concentrated in a maintenance device which is mounted within the inkjet print device, and wherein the print head can be moved over the station for maintenance. An example of such a maintenance device can be found in U.S. Pat. No. 6,193,353 (HEWLETT PACKARD) combining wiping, capping, spitting and purging functions.
During a maintenance method, such as purging, relatively large quantities of liquid are released by the inkjet print head into the maintenance device. This purged liquid can remain in the maintenance device and can afterwards dry and form, over a longer period of time, large dried liquid residues, such as stalagmite forming of dried liquid in a spittoon.
Therefore usually a system for removal of the purged liquid and dried particles is provided but they are not effective and don't evacuate the received liquid easily and fast.
For the same reason liquid fog, also called aerosol of liquid, that is released during maintenance method, such as spitting, is not evacuated easily which contaminates the inkjet print device, such as the liquid ejection surface of an inkjet print head, and may give the opportunity for inhalation by the operator.
It is clear there is a need for an improved maintenance device to provide a clean system wherein the operator and structure in the inkjet print device such as inkjet print head and any type of sensors can not be contaminated by liquid spatter and liquid fog.
An example of a maintenance unit, more specific a capping unit for an inkjet print head, is disclosed in EP1083052 (SEIKO EPSON) wherein a filter, in here called as liquid absorption member, is disclosed in FIG. 30 to filter and absorb the ink after it is received in a waste liquid receiver. There is no solution in this disclosure to evacuate the liquid fast to prevent contaminating the inkjet print device or inhalation of fog by the operator.
Another example of a maintenance unit is disclosed in US2011298875 (KOBASHI MASARU) wherein a contact member is in contact with the inkjet print head and the contact member comprises flow channels which may to allow a passage through the contact member as disclosed in [0076] but is silent about the fast evacuation of the liquid to prevent contamination the inkjet print device or inhalation of fog by the operator. Also the contact of the maintenance unit with the inkjet print head is odious because it causes scratches to the liquid ejection surface which is a disadvantage of the print quality formed by the inkjet print head after maintenance.